The Calymmian (from Greek calymma, "cover") is the first geologic period in the Mesoproterozoic Era and lasted from 1600 Ma to 1400 Ma (million years ago). Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly Geology (from Greek γη gê, "earth" and λόγος Logos, "speech" lit The Mesoproterozoic Era is a geologic era that occurred between 1600 Ma and 1000 Ma (million years ago Annum is one form of the Latin noun meaning Year, not a form normally used for derivatives in modern languages the accusative singular Instead of being based on stratigraphy, these dates are defined chronometrically. Stratigraphy, a branch of Geology, studies rock layers and layering ( stratification)
The period is characterised by expansion of existing platform covers, or by new platforms on recently cratonized basements. In Geology, a platform cover is the Sedimentary and Volcanic deposits that lie on top of a Craton. The continental shelf is the extended perimeter of each Continent and associated Coastal plain, which is covered during interglacial periods such A craton ( Greek kratos / κρἀτος ( neut. "strength" is an old and stable part of the Continental crust that has survived
The supercontinent Columbia broke up during the Calymmian some 1500 Ma. In Geology, a supercontinent is a Landmass comprising more than one Continental core or Craton. Columbia is the name of one of the Earth's oldest Supercontinents It was first proposed by J
| Proterozoic eon | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Paleoproterozoic era | Mesoproterozoic era | Neoproterozoic era | |||||||
| Siderian | Rhyacian | Orosirian | Statherian | Calymmian | Ectasian | Stenian | Tonian | Cryogenian | Ediacaran |